Tensile-strength tester.



S. N. SENNA.

TENSILE STRENGTH TESTER.

APPLICATION FILED DEC. 5. 1914.

Patented Feb. 29, 1916.

INVENTOR.

7 A TTORNE YES THE COLUMBIA PLANOGRAFH co., WASHINGTON, D. C.

sr'rns ra'rn'r r SAMUEL N. SENNA, OF HOLYOKE, MASSACHUSETTS, ASSIGN OR 0F ONE-HALF TO CHARLES E. TORRANGE, 0F I-IOLYOKE, MASSACHUSETTS.

I TENSILE-STRENGTH TESTER.

Application filed December 5, 1914.

To all whom it may concern:

Be it known that I, SAMUEL N. SENNA, a citizen of the United States of America, residing at Holyoke, in the county of Hampden and State-of Massachusetts, have invented a new and useful Tensile-Strength Tester, of which the following is a specification.

My invention relates to improvements in machines for testing the tensile strength of various thin materials, such as paper and other fabrics, leathers, celluloid, and the like, and resides in certain peculiar resilient clamping means, piston-driven hydraulic rupturing means, in connection with which is used a rubber diaphragm of the old Mullen tester type, and operating mechanism for said clamping and rupturing means, together with such auxiliary and subsidiary parts and, members as may be required or desired in order to make the tester complete and serviceable, all as hereinafter set forth. The objects of my invention are, first, to provide a hydraulic tester, having a rubber diaphragm, with powerful, uniformly-increasing-pressure clamping means for the sample while being tested; second, to furnish a tester with means to secure the sample before the actual test is made, and with means for making the test, by puncturing the sample or causing it to be punctured, after said sample is secured; third, to provide constant-speed and easily controllable driving means for the reciprocable parts, and, fourth, to produce a strong and durable tester that is comparatively simple in construction and operation, accurate, and withal entirely practicable and efficient. 7

Heretofore much trouble has been experienced with the common type "of testers, because of the insufiicient or, ineflicient clamping means for the sample, with which such machines are equipped, and it has been my, aim, successfully. achieved, entirely to eliminate any trouble of this nature from the present tester.

Speed and clamping variations are the most common sources of inaccuracy in a tester of the class herein referred to, but

with my machine these sources of inaccuracy are entirely eliminated.

Other objects and advantages will appear in the course of the following description. I attain the objects secure the advan- Specification of Letters Patent.

Serial No. 875,719.

tages of my invention by the means illustrated in the accompanying drawings, in which Figure 1 is a longitudinal central vertical section through a tester which embodies a practical form of my invention, the motor and its support being shown in elevation, and, Fig. 2, a detail of parts of the cam shaft and clutch-operating mechanism.

Similar numerals refer to similar parts throughout the several views.

In the form of the tester illustrated in connection herewith, a supporting frame 1 is provided, said frame being mounted on a bed plate 2, and, since I prefer to employ en electric motor with which to operate the tester mechanism, I have represented the same at 3, and shown it mounted on a support 4, which latter is also mounted on said plate. In order to obtain strength and rigidity in the frame 1 at the testing point, I prefer to make said frame at one end, the front end, of the punch type. This is done by cutting out the frame 1 at 5 and thus forming a head 6 above and a foot or base 7 below. The recess 5 also affords ea clear space for the work. At the top of the frame 1 are two bearings 8 for a horizontal shaft 9. Within the frame is a horizontal fluid chamber 10 which opens at one end into a vertical cylinder 11 located in the approximate center of said frame and opening through the top thereof, and at the other end through the top of the base 7. An opening 12 is formed in the front end of the frame 1 and communicates with the adjacent end of the chamber 10. The openinch is registered, such gage being attached at the outer end of said passage. This gage is not shown. because it is old and well known in the art and forms no part of the present invention. The chamber 10 is designed to contain a quantity of liquid or fluid preferably glycerin. A piston 13 is provided to operate in the cylinder 11, and said cylinder may be lined with a brass bushing 14: for the purpose of preventing said piston from-sticking.

The motor 3 has a shaft 15 which extends beneath the rear terminal portion of the shaft 9 and at right-angles thereto. Secured on the motor shaft 15 is a Worm 16, Inter-j Patented Feb. 29, 1916.

' unscrewing the nut 26 and taking off the said piston.

meshing with the worm 16 is a worm-gear 17 which is loosely mounted on the shaft 9 behind the vertical plane of the rear end of the frame 1. A bracket 18 extends rearwardly from the back end of the frame 1, and a housing 19, for the worm 16, is secured to said bracket. Rising from the housing 19 is a gear-case 20 for the worm-gear 17. The housing and gear-case are of usual construction, being made in sections which are bolted or screwed together.

Before proceeding to describe in further detail the driving mechanism of the tester, of which the worm 16 and the worm-gear 17 are essential parts, I will take up the other elements.

A platform or table 21 has a stem 22 which is screwed or otherwise securely and firmly fastened to or in the base 7, and a vertical passage'23 extends clear through said table and stem, such passage opening at the bottom into the front end of the chamber 10. The circular area of the passage 23 is usually equal to one square inch. Placed on the table 21 over the top of the passage 23 is a rubber diaphragm 24, a plate 25 and a nut 26 being employed to hold said diaphragm securely and prevent displacement thereof, A pin 27 is set in the top of the table 21, beyond the edge of the diaphragm 24, and projects into the plate 25 to prevent the same from turning while the nut 26 is being screwed into place on said table or removed therefrom. The nut 26, which is angular in cross-sections as shown, is adapted to fit over the outer rim or edge of the plate 25, when said plateis in place on the table 21 with the diaphragm between said table and said plate, and to be screwed onto the said table, the latter having an externally threaded part for that purpose.

here is a central opening 28 in the plate 25, which opening is directly over the passage 23, with the diaphragm 24: between, and of the same diameter as that of said passage.

The diaphragm 2 1 is released by simply plate 25, and the same or another diaphragm is secured in place with equal facility, as will be readily understood. Since the diaphragm is itself liable to rupture while in the act of making a test by rupturing a sample on the table, it is desirable to have convenient holding and releasing means for the diaphragm, so that a ruptured or defective, diaphragm can be easily and quickly replaced with a perfect one. A packing-ring 29 is inserted between the base 7' and the table 21 to insure a tight joint at that, place.

The piston 13 may be hollow, and it is packed at the base, to prevent leakage,-by means of a cup-packing 30 .held in place by a screw 31 tapped into the bottom of At the top of the piston 13, above the cylinder 11, is a yoke 32 which is equipped with an anti-friction roller or follower 33. Secured on the shaft 9 above the follower 33 is an eccentric or cam 34. A

spring encircles the piston 13, between the top of the cylinder 11 and the yoke 32, and tends always to force said piston upward and to retain the follower 33 in contact with the cam 31. By means of the cam 34. and with the assistance of the spring 35 the piston is reciprocated. A pin 36 extends from the piston 13 into a vertical slot 37 in the bushing 14, and moves up and down in said slot as said piston reciprocates, the purpose of said pin being to prevent the parts from turning and so throwing the follower 33 out of its proper relation to the cam 34 In reciprocating, the plunger 13 at each downward stroke acts on the fluid in the chamber 10 and the passage 23, tends to compress the same, and forces it upward in said passage against the underside of the diaphragm 21-, with the result that said dia phragm is expanded upwardly into and rupture the sample, so that nothing further need be said concerning the same.

The head 6 is bored vertically, the upper V and major portion of the bore being enlarged to form a chamber 38. A hollow plunger 39, is provided to reciprocate in and through the constricted 'or smaller bored part of the head 6, and'has an external flange 10 at the top, which flange has a sliding fit in the chamber 38. Screwedon or otherwise fastened to the plunger 39,below the head 6,'is a tripod 41 which carries at the bottom a circular plate or clamp 42.

Since the axial center of the plunger '39 is 7 directly over the axial center of the table .21, the'clamp -12 is located directly over or above .said table. The clamp 12 has a cen tral opening 43 therein to accommodate the diaphragm 2& when expanded and the portion of the sample that is ruptured or tested, said clamp then being down on the plate 25. as will presently appear. circles that portion of the plunger 39 that A spring 44: en-

is in the chamber 38, between the bottomof said chamber and the'flange 40, and tends to force upwardly said plunger with the tripod 11 and clamp 42.

Arranged to reciprocate vertically in the plunger 39 is a solid plunger or rod 15.

This rod has. a yoke 46 at the top, which yoke is equipped with an anti-friction roller or follower 47. A shoulder 48 at the base of the yoke 46 operates in the upper part of the chamber 38 and has a sliding fit therein to steady the rod 45.' A heavy calibrated spiral spring 49 is located in the chamber 38 between the top of the plunger 39 and the shoulder 48, and the rod 45 with the yoke 46 therefore being directly above the follower 47. The follower 47 is retained in constant contact with the cam-5O by means of the spring 44 which is seated on the annular floor of the chamber 38 and acts through the plunger 39 or its flange 40, the spring 49, and the yoke 46. Initially the cam 50 is disposed with its low part in contact with the follower 47. As a means to maintain the follower 47 in its true relation to the cam 50, a lug 51 may be provided on the shoulder 48 and a longitudinal slot 52 in the head 6 for said lug. The slot 52 must be long enough to accommodate the travel of the lug 51 as the latter moves with the parts actuated by the cam 50; and the slot 37 also must be of sutlicient length to accommodate the travel of the pin 36 as said pin moves with the piston 13. The cam 50 has a throw that is suflicient to vinsure adequate clamping pressure before the test actually occurs, and

the two cams](34 and 50) must bearranged or timed with that end in view. The throw of the cam 34 issnflicient to produce the required amount of action on the part of the fluid in the chamber 10 and under the diaphragm 24. The adjacent surfaces of the clamp 42 and the plate 25 are corrugated to enable them more firmly to grip the sample while the test is being made.

The shaft 9 is held against endwise movement by the bearings 8 and the contiguous cams or cam hubs. A collar 53, which is secured on the shaft 9 immediately back of the gear-case 20, and a collar '54, which is secured on said shaft immediately in front of the hub of the wormgear 1,7, prevent said worm-gear from moving axially on said shaft. Extending forward from and integral with the hub of the worm-gear 17 is an annular clutch member 55. Mounted on the shaft 9, in front of the clutch member 55 and designed to engage and release the latter, is a hollow clutch member 56. The shaft represented at 58. The slots 58 are adjacent to the forward end of the clutch member 56, and open into the passage 57. A shipper rod 59 extends into and'operates in the passage 57, and also projects from the open end of said passage. On the rear end of the rod 59 is a handle 60. A transverse pin 61 con nects the rod 59 with the member 56, such pin passing through the slots 58 and operating therein. The slots 58 must be of suflicient length, as must also the passage 57, to enable the pin 61 to be moved the necessary distance to throw the clutch out and in. A spring 62 is interposed, within the two clutch members, between the collar 54 and the closed end of the member 56, and the tendency of such spring is to force said member 56 away from the member 55. The handle 60 is loosely mounted on the rod 59, but prevented from becoming detached therefrom by a screw, 63 which passes through the outer end of said handle into threaded engagement with the adjacentend of said rod. Extending forward from the front end of the handle 60, which end encircles the rod 59, is a pair of fingers 64. The fingers 64 are so proportioned that their front ends may rest on the back end of the shaft 9, when the rod 59 is drawn rearwardly to cause the member 56 to engage the member 55, and so retain said member 56 in engagement with said member 55. Slots are cut in the back end of the shaft 9 to receive the fingers 64, when the member 56 is released to the spring 62, and thus to enable such release to take place, the handle 60 being turned on the rod 59 and the screw 63 at such time in order to move said fingers into line with said slots. One of the aforesaid slots is clearly shown at 65 in Fig. 2. The clutch is represented as being thrown out in. Fig. 1, while the clutch-operating members shown in Fig. 2 are disposed in the manner required in order to throw in said clutch.

To throw in the clutch and start the machine, the handle 60 is grasped and moved rearwardly to draw more of the. rod 59 from the shaft 9 and force the member 56, through the medium of the pin 61 and against the resiliency of the spring 62, into engagement with the member 55. The pin 6l is now in the rear ends of the slots 58.

Assuming that the motor 8 is running and driving the worm-gear 17, through the medium of the shaft 15 and the worm 16, as soon as the clutch is thrown in the shaft 9 with the cams 34 and 50 is set in motion, through the medium of the clutch members and the pin 61 which rotatably connects the member 56 with said shaft, and said shaft continues to revolve until the clutch is again thrown out. .The member 56 may be secured or maintained in engagement wit the member 55 by releasing the handle 60 when theparts are s positioned relatively that the fingers 64 engage the extreme end of the shaft 9.

To throw out the clutch and stop the machine, without shutting off the current from the motor, hold or turn the handle 60 in such a way as to cause the fingers 64 to ride into the slots 65'. This action releases the member 56 to the spring 62 and the latter actuates said member out of engagement with the member 55, the pin 61 then being moved forward in the slots 58 and the rod 59 being carried farther into the passage 57. The worm-gear 17 only stops when the current is shut off from the motor. The driven parts revolve very slowly owing to the difference in diameter between the worm and worm-gear.

In making a test the sample is placed on the plate 25, while the follower 47 is in contact with the low part of the cam 50, and the clutch is thrown in if not already in. The cam 50 commences to revolve. and first forces the clamp 42 down onto the sample and the plate 25, through the medium of the follower 47, the yoke 46 with its shoulder 48, the substantially inert spring'49, and the plunger 39 with the attached tripod 41, and against the resiliency of the spring44. As the cam 50 continues its revolution and as soon as the clamp 42 meets with the resistance offered by the table 21, the spring 49 is compressed between the shoulder 48 and the plunger 39, the plunger rod 45 descending farther into the plunger 39, with the re-" suit that said clamp is forced onto the sample with a great amount of pressure, owing to the strength and power of the spring 49.

'The sample is now gripped between the clamp. 42 and. the plate-'25 with a force that can not be broken, or from which the sample can not be loosened at any even the most minute point. Bythis time the cam 34 has rotated sufficiently to begin to "depress the follower 33 and with it the plunger 13,.

against the resiliency of the spring 35. The descending plunger 13 tends to compress or displaces the fluid beneath it and in the chamber 10 and the passage 23 and forces said fluid against the rubber diaphragm 24, thus stretching the latter and forcing it up through the plate opening 28 against the sample over said opening until, while the cam 34 is still rotating and before the high;

partithereof passes the follower 33, said stretched or expanded diaphragm ruptures said'sample. The rupturing of the sample does not take place until the maximum clamping pressure on the sample has been attained; in fact, the diaphragm 25 may not come'into contact with the sample until the'maximum or approximately maximum clamping pressure is applied to the sample. The diaphragm 24 expands into the recess or opening 43 in the clamp42, and carries Withit the contiguous portion of the san cam 50 is once more in contact with the follower 47 themembers controlled thereby are 7 in initial position and ready for the next cycle. Meanwhile the high part of the cam 34 has ridden away from the follower 33 and the spring 35 has elevated the plunger 13, so that the pressure on the fluid is relieved andthe diaphragm 24permittedt0 contract and assume its normal condition and position under the opening 28. The

mechanism is now ready to make the test on the next sample.

The cam-actuated mechanism may be stopped and started at each cycle or may be permitted to continue in operation during the'entire time that the machine is in use for makingtests, the stopping and starting in any event being effected by means of'the rod 59 and its handle 60. WVhen the machine as a whole is permitted to run continually, the operator has nothing'to'do, after 'oncestarting the cams, but to'insert and remove the samples one'after another, stopping the mechanism only after the completion of the entire series of tests.

Although I have shown and described one embodiment of my invention, itis to be understood that said invention is not restricted to such embodiment, but is broad and comprehensive enough to in'clude all structures wherein are employed resilient'means for producing clamping pressure in combination with means for producing hydraulic pressure, or canractuated clamping pressure .and hydraulic pressure-producing means, provided such structures come within the scope of my claims.

What I claim as my invention, ,and desire to secure by Letters Patent, is

. 1. A-tensile strength tester comprising direct-acting resilient clamping means, means to'overcom'e the resistance offered by-said 7 first-mentioned means and to actuate the latter into clamping position, hydraulic pres sure-producing means consistingin part of a reciprocable member in parallel relation with said first-mentioned means, a rupturing,

element in line with the axial center of'said clamping means, said rupturing element be-- ing operated by said hydraulic pressureproducmg means, and means to operate said hydraulic pressure-producingmeans. r

' r in parallel relation With said first-mentioned 2. A tensile strength tester comprising direct-acting cam-actuated pressure-producing means adapted to produce, under the action of the cam, a clamping eflect,'cam actuated hydraulic pressure-producing means consisting in part of a reciprocable member in parallel relation ith means, and a. rupturing element operated by said hydraulic pressureproducing means.

3. A tensile strength tester comprising direct-acting resilient clamping means, means to overcome the resistance ofiered by said first-mentioned means and to actuate the latter into clamping position, hydraulic pressure-producing means consisting in part of a reciprocable member in parallel relation with said first-mentioned means, a rupturing element in line With the axial center of said clamping means, said rupturing element being operated by said hydraulic pressureproducing means, and cam mechanism to operate sa1d-hydraul1c pressure-producingmeans; i I

4. A tensile strength tester comprising di- I rentacting resilient clamping means, camance oflered by said first-mentioned means and to actuate the latter into clamping position, hydraulic pressure-producing means consisting in part of areciprocable'member means, a rupturing element in line with the axial center of said clamping means, said rupturing element'being operated by said hydraulic pressure-producing means, and

cam-mechanism for operating said hydraulic pressure-producing means.

5. A tensile strength tester comprising direct-acting cam-actuated resilient means adapted to produce, under the action of the cam, a clamping effect, such means consisting in part of spring-pressed telescoping plungers, and cam-actuated hydraulic pres sure-producing rupturing means.

6.. In a tensile strength tester, .asupporting member, a fluid chamber opening through said chamber, a yielding diaphragm secured to said member over the opening therein, direct-acting resilient means for holding a sample over said diaphragm, said resilient means consisting in part of springpressed telescoping plungers,and the axis of said resilient meansbeing in line With the center of said diaphragm, and operating means adapted to overcome the resistance offered by said resilient means and actuate the'latter into clamping position.

7. In a tensile strength tester, a supporting, member, "a "fluid chamber openingv through said member, a yielding diaphragm secured to said member, over the opening therein, direct-acting resilient means for holding asample over saiddiaphragm, said resilient means "consisting in part ofsprlng pressed telescoping plungers, and the axis of said first-mentioned said resilient means being in line With the center of said diaphragm, and power-driven operating means adapted to overcome the resistance offered by said resilient means and actuate the latterinto clamping position.

' 8. In a tensile strength tester, a supporting member, a fluid chamber opening through said member, a yielding diaphragm secured to said member over the opening therein, direct-acting resilient means for holding a sample over said diaphragm, said resilient means consisting in part of springpressed telescoping plungers, and the axis ofsaid resilient means being in line With the center of said diaphragm, and cam-operated means adapted to overcome the resistance offered by said resilient means and actuate the latter into clamping position.

9. In a tensile strength tester, a supporting member, a fluid chamber opening through said member, a yielding diaphragm secured-tosaid member over the opening therein, direct-acting resilient means. for hold-ing a sample over said diaphragm, said resilient means consisting in part of springpressed telescoping plungers, and the axis of said resilient means being in line with the center of said diaphragm, and means for overcoming the resistance oflered by said spring-pressed telescoping 'plungers, hy-

draulio pressure-producing means consist ing in part of a reciprocable member in parallel relation with said first-mentioned means, a puncturing element in line With the axial center of said resilient'means, said puncturing element being operated by said hydraulic pressure-producing means, and means to overcome the resistance ofiered by said resilient means and operate the latter in advance of said puncturing means;

11. In a tensile strength tester, a support ing member provided With a yielding diaphragm, a fluid chamber opening through such member to said diaphragm, direct-acting resilient means for holding a sample on said member over said diaphragm, said resilient holding means consisting in part of spring-pressed telescoping plungers, and the axis of said resilient holding means being in line With the center ofsaid diaphragm, pressure-applying means for the fluid in said chamber, said last-mentioned means being in parallel relation With said resilient holding means, means adapted to overcome the'resistance offered by said resilient holdingmeans and operate the latter into holding position, and means to operate said pres-. sure-a oplying means for the fluid. i 12. n a tensile strength tester, a supportsaid member over said diaphragm, the axis of said resilient means being in line with the ing member provided'with a yielding diaphragm, a fluid chamber opening through such member to said diaphragm, direct-acting resilient means for holding a sample on said member over said diaphragm, the axis of said resilient means being in line With the center of said diaphragm, pressure-applying means for the fluid in said chamber, and means adapted first to overcome the resistance offered by said resilient holding means and operate the same into holdingapplying means for the fluid in said chamber, and means. automatically to operate said resilient holding means and said pressureapplying means. r

'14. In a tensile strength tester, a supporting member provided With a yielding diaphragm, a fluid chamber opening through said member to said diaphragm,

resilient means for holding a sample on said member over said diaphragm, pressure-applying means for the fluid in said chamber, and automatic means adapted first topperate said holding means and then to operate said pressure-applying means.

15. In a tensile strength tester, a supporting member provided With a yielding diaphragm, a fluid chamber opening through said member to said diaphragm, direct-acting resilient means for holding a sample on center of said diaphragm, pressure-applying means for the fluid in said chamber, and

power-driven means to operate said resilient holding means and, said pressure-applying means. 1

16. In a tensile strength tester, a supporting member provided With a yielding diaphragm, a fluid chamber opening through said member to said diaphragm, resilient means for holding a sample on said member over said diaphragm, pressure-applying means for the fluid in said chamber, and power-driven means adapted first to oper ate said holding means and then to operate said pressure-applying means.

17 In a tensile strength tester, a supporting member provided With a yielding diaphragm, a fluid chamber openingjthrough said member to said diaphragm, direct-acting resilient means for holding a sample on said member over said diaphragm, said resilient means consisting in partfof spring,

pressed telescoping plungers, and the axis of said resilient means being in line with the center of said diaphragm, pressure-applying means for the'fluid in said chamber, said last-mentioned means consisting in part overcoming the resistance offered by said resilient means and operat ng the sameto produce a uniformly-increasing pressure on I said sample, and means-for operating said pressure-applying means.

18. In atensile strength tester, supporting member provided With a yielding diaphragm, a fluid chamber opening through said member to said diaphragm, direct-act ing resilient means for holding a sampleon said member over said diaphragm, sald resilient means consisting in part of springpressedtelescoping plungers, and the axis of sa d resilient means belng 1n line with the center of said diaphragm, pressure-applying means for the fluid in said chamber, said. last-mentloned means consisting 1n part of a reciprocable member in parallelv relation W1th sald resihent means, means forovercoming the resistance offered by said re'sili ent means and operatlng the same to pro-g:

duce a uniformly-increasing pressure ,on said sample, and means to cause said pressure-applying means to operate. 19. A tensile strength tester comprising a supporting member provided with a yield; ing diaphragm, afluid chamber opening through saidmember'to said diaphragm,

direct-acting resilient clamping means for a:

sample While being tested, said resilient means consisting inpart of spring-pressed telescoping plungers, and the axis of said resilient means beingin line With the center of said diaphragm, means adapted'to overcome the resistance oflered by. said resilient means and actuate the same into clamping posltion, pressure-applying means for the fluid in said chamber, said last-mentioned 7 means consisting in part of a reciprocable member in parallel relation with said resilient clamp ng means, and means to actuate said pressure-applying means after a predetermined pressure has been exerted on'said sample by said clampmg means.

20, The combination, in a tensile strength tester, with a' supporting member provided with a yielding diaphragm, a fluid chamber opening through said member to said diaphragm, and pressure-applying means, for

said supporting member, a spring adapted --to be compressed when said clampis brought into contact Withsaid supporting member,

and means to actuate said telescoping mem-' bers and compress-said spring. r

the fluid in said chamber, of reciprocable I telescoping members carrying a clamp over opening through said: member to said diaphragm, and pressure-applylng means for the fluid in said chamber, of reoiprocable telescoping members provided with a followerlat one terminal and carrying a clamp at the other-terminal over said supporting member, a spring adapted to be compressed when said clamp is brought into contact with said supporting member, a cam for resilient means to hold a sample onsaid support over said diaphragm during the action on said sample ofr said diaphragm while, subjected to the fluid under pressure in said chamber from said piston.

23. The combination, in a tensile strength tester, with a supporting member provided with a yielding diaphragm, a fluid chamber opening through-said member to said diaphragm, a cylinder communicating with Copies of this patent may be obtained for said chamber, a piston in said cylinder, and means to operate sald piston, of reciprocable telescoping members carrying a clamp over said. supporting member, a spring adaptedto be compressed when said clamp Y is brought into contact with said supporting 'member, and means to actuate said tele- SCOPillg members and compress said spring.

24. The combination, in a tensile strength tester, with a supporting member provided with a yielding diaphragm, a fluid chamber opening through said member to said diaphragm, a cylinder communicating with said chamber, and a cam-actuated piston in said cylinder,tof cam-actuated telescoping members carrying a clamp over said supporting member, and a spring adapted to be compressed when said clamp is brought into contact with said supporting member.

25. In a tensile strength tester, a table havinga passage'therethrough, a rubber diaphragm, a perforated plate, means to prevent said plate from turning on said table, and a nut' adapted to be screwed onto said table over the rimof said plate, with said diaphragm between said table and said plate.

SAMUEL N. SENNA. Witnesses a F. A. CUTTER, A. C. FAIRBANK.

five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

